Sodium polyacrylate immersed in water

On Monday, ZDNet UK visited the Royal Society's annual Summer Science Exhibition, which brings together cutting-edge science and technology projects under way at British universities.

In one exhibit, academics from the University of St Andrews demonstrated
various approaches to render objects invisible.

One method is to use materials with the same reflective properties as their background. To demonstrate this, the university researchers filled a container with a mixture of water and geometric
shapes made of sodium polyacrylate. Because the reflectivity of sodium polyacrylate is the same as
that of water, light does not bounce off an object made of the material when it is immersed in the liquid. Instead, it passes through the material and the water at the same rate, making the object nearly impossible to see.

While this technique is a helpful illustration of invisibility via reflectivity, it is impractical because to use it the object must be entirely composed of sodium polyacrylate, a spokesman for St Andrews conceded.

Photo credit: Jack Clark

Published: July 5, 2011 -- 15:54 GMT (08:54 PDT)

Caption by: Jack Clark

Retinal implant for retinitis pigmentosa blindness

Oxford University researchers demonstrated a retinal implant for restoring sight to individuals who suffer from the retinitis pigmentosa family of degenerative vision conditions.

The implant replaces the eye's light-sensitive receptors with an array of around 1,500 receptors affixed to the implantable cell (pictured, bottom left). Each receptor is attached to a photocell, to detect light as it falls into the retina of the implantee; an amplifying circuit, to boost the generated signal; and a stimulation electrode to pass information on to the brain.

A person with this implant will no longer be blind, and will instead see a pixelated view of the world in black, white and the shades in between, according to Retina Implant, which manufactures the device.

Oxford University researchers will lead a clinical trial to implant the device into UK patients who have become blind in at least one eye due to retinitis pigmentosa. The trial is set to begin in September. The implant is powered by an inductive coil (pictured, top left), which sits behind the person's ear, under the skin.

Published: July 5, 2011 -- 15:54 GMT (08:54 PDT)

Photo by: Jack Clark

Caption by: Jack Clark

Low-resolution retinal implant

Pictured above is a simulation of how those fitted with the implant view the world. A spokesman from Oxford University said that in actual cases, patients report the view is significantly more blurred than what is depicted, with vaguer gaps between each point. This simulation shows an eight-by-eight array of receptors and is from implants that were tested in 2009.

Published: July 5, 2011 -- 15:54 GMT (08:54 PDT)

Photo by: Jack Clark

Caption by: Jack Clark

High-resolution retinal implant

Since 2009, the technology has advanced in resolution from an eight-by-eight array to a 40-by-40 one. This shows an approximation of the images received from that latest generation of the implant. It has a fidelity of around 1,600 pixels, as opposed to 64 pixels previously.

A camera hooked up to a screen showed a simulation of the cell's output. Using this, ZDNet UK's reporter was able to distinguish himself (pictured, centre) and the movement of others behind him. The resolution was sufficient to distinguish objects roughly the size of a coffee mug held at arm's length with increasing detail at closer ranges.

A mathematically generated male face

Another exhibit covered the work of the Facing up to Faces project, carried out by Queen Mary, University of London and University College London.

The project aims to design a program that mathematically generates faces based on a set of input photos. The researchers loaded in photographs of 50 male and female faces, then applied algorithms that allow users to manipulate the settings (pictured, right) to come up with faces whose configuration lies between recorded ones.

The research team expects the technology eventually to be useful for building police photo-fits and for creating characters in CGI animations, according to a spokesman.

Photo credit: Jack Clark

Published: July 5, 2011 -- 15:54 GMT (08:54 PDT)

Caption by: Jack Clark

A mathematically-generated female face

In addition, the UCL researchers used algorithms to allow users to switch a face from male to female.

For the time being, the variety of faces that can be created is limited by how many photos are in the system. "You could have a server in Japan and input 100 Japanese faces to broaden your base," the spokesman said.

Photo credit: Jack Clark

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Eyes and invisibility at the Royal Society

A method for making objects invisible in water and retinal implants to help the blind see were among the cutting-edge projects on display at the Royal Society's annual science fair

Read Less

Sodium polyacrylate immersed in water

On Monday, ZDNet UK visited the Royal Society's annual Summer Science Exhibition, which brings together cutting-edge science and technology projects under way at British universities.

In one exhibit, academics from the University of St Andrews demonstrated
various approaches to render objects invisible.

One method is to use materials with the same reflective properties as their background. To demonstrate this, the university researchers filled a container with a mixture of water and geometric
shapes made of sodium polyacrylate. Because the reflectivity of sodium polyacrylate is the same as
that of water, light does not bounce off an object made of the material when it is immersed in the liquid. Instead, it passes through the material and the water at the same rate, making the object nearly impossible to see.

While this technique is a helpful illustration of invisibility via reflectivity, it is impractical because to use it the object must be entirely composed of sodium polyacrylate, a spokesman for St Andrews conceded.